TY - JOUR A1 - Kress, Sebastian A1 - Baur, Johannes A1 - Otto, Christoph A1 - Burkard, Natalie A1 - Braspenning, Joris A1 - Walles, Heike A1 - Nickel, Joachim A1 - Metzger, Marco T1 - Evaluation of a miniaturized biologically vascularized scaffold in vitro and in vivo JF - Scientific Reports N2 - In tissue engineering, the generation and functional maintenance of dense voluminous tissues is mainly restricted due to insufficient nutrient supply. Larger three-dimensional constructs, which exceed the nutrient diffusion limit become necrotic and/or apoptotic in long-term culture if not provided with an appropriate vascularization. Here, we established protocols for the generation of a pre-vascularized biological scaffold with intact arterio-venous capillary loops from rat intestine, which is decellularized under preservation of the feeding and draining vascular tree. Vessel integrity was proven by marker expression, media/blood reflow and endothelial LDL uptake. In vitro maintenance persisted up to 7 weeks in a bioreactor system allowing a stepwise reconstruction of fully vascularized human tissues and successful in vivo implantation for up to 4 weeks, although with time-dependent decrease of cell viability. The vascularization of the construct lead to a 1.5× increase in cellular drug release compared to a conventional static culture in vitro. For the first time, we performed proof-of-concept studies demonstrating that 3D tissues can be maintained within a miniaturized vascularized scaffold in vitro and successfully implanted after re-anastomosis to the intrinsic blood circulation in vivo. We hypothesize that this technology could serve as a powerful platform technology in tissue engineering and regenerative medicine. KW - biological models KW - translational research Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176343 VL - 8 IS - 4719 ER - TY - JOUR A1 - Bachmann, Julia A1 - Ehlert, Elias A1 - Becker, Matthias A1 - Otto, Christoph A1 - Radeloff, Katrin A1 - Blunk, Torsten A1 - Bauer-Kreisel, Petra T1 - Ischemia-like stress conditions stimulate trophic activities of adipose-derived stromal/stem cells JF - Cells N2 - Adipose-derived stromal/stem cells (ASCs) have been shown to exert regenerative functions, which are mainly attributed to the secretion of trophic factors. Upon transplantation, ASCs are facing an ischemic environment characterized by oxygen and nutrient deprivation. However, current knowledge on the secretion capacity of ASCs under such conditions is limited. Thus, the present study focused on the secretory function of ASCs under glucose and oxygen deprivation as major components of ischemia. After exposure to glucose/oxygen deprivation, ASCs maintained distinct viability, but the metabolic activity was greatly reduced by glucose limitation. ASCs were able to secrete a broad panel of factors under glucose/oxygen deprivation as revealed by a cytokine antibody array. Quantification of selected factors by ELISA demonstrated that glucose deprivation in combination with hypoxia led to markedly higher secretion levels of the angiogenic and anti-apoptotic factors IL-6, VEGF, and stanniocalcin-1 as compared to the hypoxic condition alone. A conditioned medium of glucose/oxygen-deprived ASCs promoted the viability and tube formation of endothelial cells, and the proliferation and migration of fibroblasts. These findings indicate that ASCs are stimulated by ischemia-like stress conditions to secrete trophic factors and would be able to exert their beneficial function in an ischemic environment. KW - adipose-derived stromal/stem cells (ASCs) KW - regenerative medicine KW - secretion KW - trophic factors KW - ischemia KW - glucose starvation KW - hypoxia Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-211233 SN - 2073-4409 VL - 9 IS - 9 ER - TY - JOUR A1 - Hillmann, Steffi A1 - Wiedmann, Silke A1 - Rücker, Viktoria A1 - Berger, Klaus A1 - Nabavi, Darius A1 - Bruder, Ingo A1 - Koennecke, Hans-Christian A1 - Seidel, Günter A1 - Misselwitz, Björn A1 - Janssen, Alfred A1 - Burmeister, Christoph A1 - Matthis, Christine A1 - Busse, Otto A1 - Hermanek, Peter A1 - Heuschmann, Peter Ulrich T1 - Stroke unit care in Germany: the German stroke registers study group (ADSR) JF - BMC Neurology N2 - Background: Factors influencing access to stroke unit (SU) care and data on quality of SU care in Germany are scarce. We investigated characteristics of patients directly admitted to a SU as well as patient-related and structural factors influencing adherence to predefined indicators of quality of acute stroke care across hospitals providing SU care. Methods: Data were derived from the German Stroke Registers Study Group (ADSR), a voluntary network of 9 regional registers for monitoring quality of acute stroke care in Germany. Multivariable logistic regression analyses were performed to investigate characteristics influencing direct admission to SU. Generalized Linear Mixed Models (GLMM) were used to estimate the influence of structural hospital characteristics (percentage of patients admitted to SU, year of SU-certification, and number of stroke and TIA patients treated per year) on adherence to predefined quality indicators. Results: In 2012 180,887 patients were treated in 255 hospitals providing certified SU care participating within the ADSR were included in the analysis; of those 82.4% were directly admitted to a SU. Ischemic stroke patients without disturbances of consciousness (p < .0001), an interval onset to admission time ≤3 h (p < .0001), and weekend admission (p < .0001) were more likely to be directly admitted to a SU. A higher proportion of quality indicators within predefined target ranges were achieved in hospitals with a higher proportion of SU admission (p = 0.0002). Quality of stroke care could be maintained even if certification was several years ago. Conclusions: Differences in demographical and clinical characteristics regarding the probability of SU admission were observed. The influence of structural characteristics on adherence to evidence-based quality indicators was low. KW - stroke register KW - stroke unit care KW - quality of health care KW - quality indicators Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159447 VL - 17 IS - 49 ER - TY - JOUR A1 - Metzner, Valentin A1 - Herzog, Gloria A1 - Heckel, Tobias A1 - Bischler, Thorsten A1 - Hasinger, Julia A1 - Otto, Christoph A1 - Fassnacht, Martin A1 - Geier, Andreas A1 - Seyfried, Florian A1 - Dischinger, Ulrich T1 - Liraglutide + PYY\(_{3-36}\) combination therapy mimics effects of Roux-en-Y bypass on early NAFLD whilst lacking-behind in metabolic improvements JF - Journal of Clinical Medicine N2 - Background: Treatment options for NAFLD are still limited. Bariatric surgery, such as Roux-en-Y gastric bypass (RYGB), has been shown to improve metabolic and histologic markers of NAFLD. Glucagon-like-peptide-1 (GLP-1) analogues lead to improvements in phase 2 clinical trials. We directly compared the effects of RYGB with a treatment using liraglutide and/or peptide tyrosine tyrosine 3-36 (PYY\(_{3-36}\)) in a rat model for early NAFLD. Methods: Obese male Wistar rats (high-fat diet (HFD)-induced) were randomized into the following treatment groups: RYGB, sham-operation (sham), liraglutide (0.4 mg/kg/day), PYY\(_{3-36}\) (0.1 mg/kg/day), liraglutide+PYY\(_{3-36}\), and saline. After an observation period of 4 weeks, liver samples were histologically evaluated, ELISAs and RNA sequencing + RT-qPCRs were performed. Results: RYGB and liraglutide+PYY\(_{3-36}\) induced a similar body weight loss and, compared to sham/saline, marked histological improvements with significantly less steatosis. However, only RYGB induced significant metabolic improvements (e.g., adiponectin/leptin ratio 18.8 ± 11.8 vs. 2.4 ± 1.2 in liraglutide+PYY\(_{3-36}\)- or 1.4 ± 0.9 in sham-treated rats). Furthermore, RNA sequencing revealed a high number of differentially regulated genes in RYGB treated animals only. Conclusions: The combination therapy of liraglutide+PYY\(_{3-36}\) partly mimics the positive effects of RYGB on weight reduction and on hepatic steatosis, while its effects on metabolic function lack behind RYGB. KW - liraglutide KW - GLP-1 KW - peptide tyrosine tyrosine (PYY) KW - peptide tyrosine tyrosine 3-36 (PYY\(_{3-36}\)) KW - RYGB KW - gastric bypass KW - obesity KW - NASH KW - NAFLD Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-255244 SN - 2077-0383 VL - 11 IS - 3 ER - TY - JOUR A1 - Dischinger, Ulrich A1 - Hasinger, Julia A1 - Königsrainer, Malina A1 - Corteville, Carolin A1 - Otto, Christoph A1 - Fassnacht, Martin A1 - Hankir, Mohamed A1 - Seyfried, Florian Johannes David T1 - Toward a Medical Gastric Bypass: Chronic Feeding Studies With Liraglutide + PYY\(_{3-36}\) Combination Therapy in Diet-Induced Obese Rats JF - Frontiers in Endocrinology N2 - Background Combination therapies of anorectic gut hormones partially mimic the beneficial effects of bariatric surgery. Thus far, the effects of a combined chronic systemic administration of Glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine 3-36 (PYY\(_{3-36}\)) have not been directly compared to Roux-en-Y gastric bypass (RYGB) in a standardized experimental setting. Methods High-fat diet (HFD)-induced obese male Wistar rats were randomized into six treatment groups: (1) RYGB, (2) sham-operation (shams), (3) liraglutide, (4) PYY\(_{3-36}\), (5) PYY\(_{3-36}\)+liraglutide (6), saline. Animals were kept on a free choice high- and low-fat diet. Food intake, preference, and body weight were measured daily for 4 weeks. Open field (OP) and elevated plus maze (EPM) tests were performed. Results RYGB reduced food intake and achieved sustained weight loss. Combined PYY\(_{3-36}\)+liraglutide treatment led to similar and plateaued weight loss compared to RYGB. Combined PYY\(_{3-36}\)+liraglutide treatment was superior to PYY\(_{3-36}\) (p ≤ 0.0001) and liraglutide (p ≤ 0.05 or p ≤ 0.01) mono-therapy. PYY\(_{3-36}\)+liraglutide treatment and RYGB also reduced overall food intake and (less pronounced) high-fat preference compared to controls. The animals showed no signs of abnormal behavior in OF or EPM. Conclusions Liraglutide and PYY\(_{3-36}\) combination therapy vastly mimics reduced food intake, food choice and weight reducing benefits of RYGB. KW - obesity KW - rygb KW - liraglutide KW - peptide tyrosine tyrosine (PYY) KW - treatment KW - gastric bypass KW - peptide tyrosine tyrosine 3-36 (PYY3-36) Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223113 SN - 1664-2392 VL - 11 ER - TY - JOUR A1 - Rösch, Manfred A1 - Biester, Harald A1 - Bogenrieder, Arno A1 - Eckmeier, Eileen A1 - Ehrmann, Otto A1 - Gerlach, Renate A1 - Hall, Mathias A1 - Hartkopf-Fröder, Christoph A1 - Herrmann, Ludger A1 - Kury, Birgit A1 - Lechterbeck, Jutta A1 - Schier, Wolfram A1 - Schulz, Erhard T1 - Late neolithic agriculture in temperate Europe—a long-term experimental approach JF - Land N2 - Long-term slash-and-burn experiments, when compared with intensive tillage without manuring, resulted in a huge data set relating to potential crop yields, depending on soil quality, crop type, and agricultural measures. Cultivation without manuring or fallow phases did not produce satisfying yields, and mono-season cropping on freshly cleared and burned plots resulted in rather high yields, comparable to those produced during modern industrial agriculture - at least ten-fold the ones estimated for the medieval period. Continuous cultivation on the same plot, using imported wood from adjacent areas as fuel, causes decreasing yields over several years. The high yield of the first harvest of a slash-and-burn agriculture is caused by nutrient input through the ash produced and mobilization from the organic matter of the topsoil, due to high soil temperatures during the burning process and higher topsoil temperatures due to the soil’s black surface. The harvested crops are pure, without contamination of any weeds. Considering the amount of work required to fight weeds without burning, the slash-and-burn technique yields much better results than any other tested agricultural approach. Therefore, in dense woodland, without optimal soils and climate, slash-and-burn agriculture seems to be the best, if not the only, feasible method to start agriculture, for example, during the Late Neolithic, when agriculture expanded from the loess belt into landscapes less suitable for agriculture. Extensive and cultivation with manuring is more practical in an already-open landscape and with a denser population, but its efficiency in terms of the ratio of the manpower input to food output, is worse. Slash-and-burn agriculture is not only a phenomenon of temperate European agriculture during the Neolithic, but played a major role in land-use in forested regions worldwide, creating anthromes on a huge spatial scale. KW - Neolithic agriculture KW - experimental archaeology KW - slash-and-burn KW - temperate Europe Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-198103 SN - 2073-445X VL - 6 IS - 1 ER - TY - JOUR A1 - Klement, Rainer J. A1 - Champ, Colin E. A1 - Otto, Christoph A1 - Kämmerer, Ulrike T1 - Anti-Tumor Effects of Ketogenic Diets in Mice: A Meta-Analysis JF - PLoS ONE N2 - Background Currently ketogenic diets (KDs) are hyped as an anti-tumor intervention aimed at exploiting the metabolic abnormalities of cancer cells. However, while data in humans is sparse, translation of murine tumor models to the clinic is further hampered by small sample sizes, heterogeneous settings and mixed results concerning tumor growth retardation. The aim was therefore to synthesize the evidence for a growth inhibiting effect of KDs when used as a monotherapy in mice. Methods We conducted a Bayesian random effects meta-analysis on all studies assessing the survival (defined as the time to reach a pre-defined endpoint such as tumor volume) of mice on an unrestricted KD compared to a high carbohydrate standard diet (SD). For 12 studies meeting the inclusion criteria either a mean survival time ratio (MR) or hazard ratio (HR) between the KD and SD groups could be obtained. The posterior estimates for the MR and HR averaged over four priors on the between-study heterogeneity τ\(^{2}\) were MR = 0.85 (95% highest posterior density interval (HPDI) = [0.73, 0.97]) and HR = 0.55 (95% HPDI = [0.26, 0.87]), indicating a significant overall benefit of the KD in terms of prolonged mean survival times and reduced hazard rate. All studies that used a brain tumor model also chose a late starting point for the KD (at least one day after tumor initiation) which accounted for 26% of the heterogeneity. In this subgroup the KD was less effective (MR = 0.89, 95% HPDI = [0.76, 1.04]). Conclusions There was an overall tumor growth delaying effect of unrestricted KDs in mice. Future experiments should aim at differentiating the effects of KD timing versus tumor location, since external evidence is currently consistent with an influence of both of these factors. KW - anti-tumor effects KW - ketogenic dients KW - mice Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167036 VL - 11 IS - 5 ER - TY - JOUR A1 - Hankir, Mohammed K. A1 - Rotzinger, Laura A1 - Nordbeck, Arno A1 - Corteville, Caroline A1 - Dischinger, Ulrich A1 - Knop, Juna-Lisa A1 - Hoffmann, Annett A1 - Otto, Christoph A1 - Seyfried, Florian T1 - Leptin receptors are not required for Roux-en-Y gastric bypass surgery to normalize energy and glucose homeostasis in rats JF - Nutrients N2 - Sensitization to the adipokine leptin is a promising therapeutic strategy against obesity and its comorbidities and has been proposed to contribute to the lasting metabolic benefits of Roux-en-Y gastric bypass (RYGB) surgery. We formally tested this idea using Zucker fatty fa/fa rats as an established genetic model of obesity, glucose intolerance, and fatty liver due to leptin receptor deficiency. We show that the changes in body weight in these rats following RYGB largely overlaps with that of diet-induced obese Wistar rats with intact leptin receptors. Further, food intake and oral glucose tolerance were normalized in RYGB-treated Zucker fatty fa/fa rats to the levels of lean Zucker fatty fa/+ controls, in association with increased glucagon-like peptide 1 (GLP-1) and insulin release. In contrast, while fatty liver was also normalized in RYGB-treated Zucker fatty fa/fa rats, their circulating levels of the liver enzyme alanine aminotransferase (ALT) remained elevated at the level of obese Zucker fatty fa/fa controls. These findings suggest that the leptin system is not required for the normalization of energy and glucose homeostasis associated with RYGB, but that its potential contribution to the improvements in liver health postoperatively merits further investigation. KW - Roux-en-Y gastric bypass surgery KW - energy homeostasis KW - glucose homeostasis KW - fatty liver KW - leptin system KW - Zucker fatty fa/fa rats Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239550 SN - 2072-6643 VL - 13 IS - 5 ER - TY - JOUR A1 - Madrahimov, Nodir A1 - Mutsenko, Vitalii A1 - Natanov, Ruslan A1 - Radaković, Dejan A1 - Klapproth, André A1 - Hassan, Mohamed A1 - Rosenfeldt, Mathias A1 - Kleefeldt, Florian A1 - Aleksic, Ivan A1 - Ergün, Süleyman A1 - Otto, Christoph A1 - Leyh, Rainer G. A1 - Bening, Constanze T1 - Multiorgan recovery in a cadaver body using mild hypothermic ECMO treatment in a murine model JF - Intensive Care Medicine Experimental N2 - Background Transplant candidates on the waiting list are increasingly challenged by the lack of organs. Most of the organs can only be kept viable within very limited timeframes (e.g., mere 4–6 h for heart and lungs exposed to refrigeration temperatures ex vivo). Donation after circulatory death (DCD) using extracorporeal membrane oxygenation (ECMO) can significantly enlarge the donor pool, organ yield per donor, and shelf life. Nevertheless, clinical attempts to recover organs for transplantation after uncontrolled DCD are extremely complex and hardly reproducible. Therefore, as a preliminary strategy to fulfill this task, experimental protocols using feasible animal models are highly warranted. The primary aim of the study was to develop a model of ECMO-based cadaver organ recovery in mice. Our model mimics uncontrolled organ donation after an “out-of-hospital” sudden unexpected death with subsequent “in-hospital” cadaver management post-mortem. The secondary aim was to assess blood gas parameters, cardiac activity as well as overall organ state. The study protocol included post-mortem heparin–streptokinase administration 10 min after confirmed death induced by cervical dislocation under full anesthesia. After cannulation, veno-arterial ECMO (V–A ECMO) was started 1 h after death and continued for 2 h under mild hypothermic conditions followed by organ harvest. Pressure- and flow-controlled oxygenated blood-based reperfusion of a cadaver body was accompanied by blood gas analysis (BGA), electrocardiography, and histological evaluation of ischemia–reperfusion injury. For the first time, we designed and implemented, a not yet reported, miniaturized murine hemodialysis circuit for the treatment of severe hyperkalemia and metabolic acidosis post-mortem. Results BGA parameters confirmed profound ischemia typical for cadavers and incompatible with normal physiology, including extremely low blood pH, profound negative base excess, and enormously high levels of lactate. Two hours after ECMO implantation, blood pH values of a cadaver body restored from < 6.5 to 7.3 ± 0.05, pCO2 was lowered from > 130 to 41.7 ± 10.5 mmHg, sO2, base excess, and HCO3 were all elevated from below detection thresholds to 99.5 ± 0.6%, − 4 ± 6.2 and 22.0 ± 6.0 mmol/L, respectively (Student T test, p < 0.05). A substantial decrease in hyperlactatemia (from > 20 to 10.5 ± 1.7 mmol/L) and hyperkalemia (from > 9 to 6.9 ± 1.0 mmol/L) was observed when hemodialysis was implemented. On balance, the first signs of regained heart activity appeared on average 10 min after ECMO initiation without cardioplegia or any inotropic and vasopressor support. This was followed by restoration of myocardial contractility with a heart rate of up to 200 beats per minute (bpm) as detected by an electrocardiogram (ECG). Histological examinations revealed no evidence of heart injury 3 h post-mortem, whereas shock-specific morphological changes relevant to acute death and consequent cardiac/circulatory arrest were observed in the lungs, liver, and kidney of both control and ECMO-treated cadaver mice. Conclusions Thus, our model represents a promising approach to facilitate studying perspectives of cadaveric multiorgan recovery for transplantation. Moreover, it opens new possibilities for cadaver organ treatment to extend and potentiate donation and, hence, contribute to solving the organ shortage dilemma. KW - extracorporeal membrane oxygenation KW - cadaver multiorgan preservation KW - mild hypothermia KW - post-mortem heart recovery Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357381 VL - 11 ER - TY - JOUR A1 - Zaitseva, Olena A1 - Hoffmann, Annett A1 - Löst, Margaretha A1 - Anany, Mohamed A. A1 - Zhang, Tengyu A1 - Kucka, Kirstin A1 - Wiegering, Armin A1 - Otto, Christoph A1 - Wajant, Harald T1 - Antibody-based soluble and membrane-bound TWEAK mimicking agonists with FcγR-independent activity JF - Frontiers in Immunology N2 - Fibroblast growth factor (FGF)-inducible 14 (Fn14) activates the classical and alternative NFκB (nuclear factor ‘kappa-light-chain-enhancer’ of activated B-cells) signaling pathway but also enhances tumor necrosis factor (TNF)-induced cell death. Fn14 expression is upregulated in non-hematopoietic cells during tissue injury and is also often highly expressed in solid cancers. In view of the latter, there were and are considerable preclinical efforts to target Fn14 for tumor therapy, either by exploiting Fn14 as a target for antibodies with cytotoxic activity (e.g. antibody-dependent cellular cytotoxicity (ADCC)-inducing IgG variants, antibody drug conjugates) or by blocking antibodies with the aim to interfere with protumoral Fn14 activities. Noteworthy, there are yet no attempts to target Fn14 with agonistic Fc effector function silenced antibodies to unleash the proinflammatory and cell death-enhancing activities of this receptor for tumor therapy. This is certainly not at least due to the fact that anti-Fn14 antibodies only act as effective agonists when they are presented bound to Fcγ receptors (FcγR). Thus, there are so far no antibodies that robustly and selectively engage Fn14 signaling without triggering unwanted FcγR-mediated activities. In this study, we investigated a panel of variants of the anti-Fn14 antibody 18D1 of different valencies and domain architectures with respect to their inherent FcγR-independent ability to trigger Fn14-associated signaling pathways. In contrast to conventional 18D1, the majority of 18D1 antibody variants with four or more Fn14 binding sites displayed a strong ability to trigger the alternative NFκB pathway and to enhance TNF-induced cell death and therefore resemble in their activity soluble (TNF)-like weak inducer of apoptosis (TWEAK), one form of the natural occurring ligand of Fn14. Noteworthy, activation of the classical NFκB pathway, which naturally is predominately triggered by membrane-bound TWEAK but not soluble TWEAK, was preferentially observed with a subset of constructs containing Fn14 binding sites at opposing sites of the IgG scaffold, e.g. IgG1-scFv fusion proteins. A superior ability of IgG1-scFv fusion proteins to trigger classical NFκB signaling was also observed with the anti-Fn14 antibody PDL192 suggesting that we identified generic structures for Fn14 antibody variants mimicking soluble and membrane-bound TWEAK. KW - agonistic antibodies KW - cell death KW - FcγR KW - Fn14 KW - NFκB KW - TNF receptor superfamily KW - TWEAK Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-323116 VL - 14 ER -